The Clinical Core goals are to enroll, thoroughly clinically evaluate and characterize, and longitudinally follow elderly persons from diverse ethnic backgrounds, over the spectrum from those without dementia, to those with mild cognitive impairment (MCI), and with Alzheimer's disease and related dementias. The objectives are to further understanding of the etiologies of MCI in a community-representative sample of elderly individuals of differing cultural, ethnic, and socioeconomic origins, to assess factors involved in development of MCI and conversion of MCI to AD, and to provide well-characterized patients for research projects. The core will recruit a new cohort from a special population of about 500 community or apartment-dwelling individuals who receive home health care from nearby Isabella Geriatric Center. Most of these are not demented; most are Hispanic or African American. The focus will be assessment and follow-up of MCI, and the contributions of co-morbidities. The core will provide well-characterized subjects for research studies into aging and dementia, and will follow these subjects to autopsy. Rigorous standardized subject evaluations will include medical and neurological examinations, and neuropsychological and laboratory testing. Neuroimaging using MRJ will be performed in a subset of subjects. The value of brain autopsy will be emphasized, and the core will continue close interaction with the Neuropathology Core, since autopsy neuropathological examination generates definitive data regarding the disease processes during life, and also provides valuable brain tissue for proteomic, gene expression, mitochondrial, biochemical and genomic biological investigations. The Core will interact closely with the Data Management and Statistical Core, to ensure complete and highly standardized data collection and entry, allow consistent data analysis within the ADRC and allied projects that utilize ADRC subjects, and facilitate data transfer as specified by the National Alzheimer's Coordinating Center (NACC). Clinical Core activities will be a resource for a large number of federal, pharmaceutical, and foundation research projects, including clinical drug trials, neuroimaging studies, neuropsychological instrument trials, and research studies on risk factors.